Battery-powered wheelchairs have afforded the temporarily and permanently disabled person a new freedom of movement. For the paraplegic who has use of a hand or hands, control of movement of the wheelchair can be readily accomplished by means of hand-operated controls. A typical battery-powered or motorized wheelchair and a hand-operated controller is shown in U.S. Pat. No. 3,807,520. A similar wheelchair and hand-operated controller is shown in U.S. Pat. No. 3,802,524, with the controller in this patent additionally being formed for mounting on the back of the wheelchair for hand operation by an attendant walking behind the chair.
A quadriplegic cannot avail himself of the hand-operated controller, and attempts have been made to devise head-operated or actuated wheelchair controllers. One apparatus which has been commercially developed employs a chain rest which is positioned in front of the user and is connected to a rheostat-type controller. The chin rest is mounted to a lever arm which is universally mounted for displacement, and the chin of the user of the wheelchair is used to displace the control lever by pushing on the chin rest in a predetermined direction. Another similar commercially available controller employs a mouth stick or lever which is gripped between the teeth of the user. Again, the mouth stick is selectively displaced to control wheelchair motion through a rheostat controller.
While satisfactory for some applications, such commercially available wheelchair controllers for quadriplegics have been found to have substantial disadvantages. The basic problem that exists with chin rest and mouth stick controllers is that uneven and bumpy terrain can cause the user's head to bob or bounce, which is translated into spurious control signals to the wheelchair. Thus, uneven terrain can cause erratic movement which in turn feeds upon itself causing further spurious head movements and unwanted wheelchair control commands. Since the inertia of the person using the chair is forward and toward the control lever, it can be most difficult and sometimes impossible and highly dangerous to pull back away from the controller. This problem is accentuated on inclined surfaces. Thus, stopping when going downhill is uncertain and erratic, and gravity works against the user's head when going uphill.
Another head actuated wheelchair control system is shown in U.S. Pat. No. 3,374,845. In this system, a gravity based sensor is carried in a helmet worn by the disabled person. The helmet can then be tilted in predetermined direction so as to control wheelchair motion. In addition to being a relatively complex system, this approach similarly has the problem, which the patented system attempts to overcome by more apparatus, of bobbing, bouncing and weaving of the head of the patient when the chair is in motion. This head movement will again induce erratic wheelchair movement, which tends to feed back and accentuate or cause further head movement.
In addition to being able to control the forward or rearward motion of a wheelchair, it is highly desirable for the patient to be able to control his attitude or positioning in the chair by movements of portions of the chair. More particularly, it is highly desirable that the wheelchair user be able to periodically change the orientation of the back of the wheelchair with respect to the seat. Such change in orientation serves at least four purposes. First, it can allow the user to achieve the most comfortable position for him or her. Secondly, orientation of the back of the chair to different attitudes can greatly facilitate control of the wheelchair during motion, e.g., when going uphill or downhill. Thirdly, if the orientation of the back can be adjusted periodically about the most comfortable position, the incidence of decubitus ulcers resulting from pressure on body contact points can be reduced. Lastly, the chair back can be reclined to a fully prone position to enable resting. While wheelchairs which have backs that can be fully reclined to the prone position are well known, for example, see U.S. Pat. No. 3,111,181, the control mechanisms for such chairs have not been suitable for use by the quadriplegic.
Accordingly, it is an object of the present invention to provide a wheelchair control apparatus which can be used as a head actuatable control center for the motion and orientation of a wheelchair.
Another object of the present invention is to provide a head actuated control apparatus for use in controlling a battery-powered wheelchair which apparatus substantially eliminates the dynamic feedback from chair motion which can cause erratic movement.
It is a further object of the present invention to provide head actuated control apparatus for a wheelchair which will allow adjustment of the orientation of the wheelchair back to enable better control of the motion of the wheelchair.
It is a further object of the present invention to provide head actuated control apparatus for a battery-powered wheelchair which can be readily adjusted to accommodate the physical stature of disabled individuals.
It is a further object of the present invention to provide head actuated control apparatus for a battery-powered wheelchair which is relatively simple to construct and install, requires little training to master its use, is durable, and can be adapted for use on a wide variety of wheelchairs.
The head actuated control apparatus of the present invention has other objects and features of advantage, some of which will become more apparent from or are set forth in the following description and accompanying drawing.